Specifications

The Antec Earthwatts EA-550 Platinum is an 80 Plus Platinum certified PSU, which guarantees its efficiency to be around 90 per cent at all loads. In other words, that's a guarantee that this supply is going to be cheap to run.

The certification was proved correct in our testing, with the PSU managing 91.31 per cent efficiency at 100 per cent load, 92.86 per cent at 50 per cent load and 90.76 per cent at 20 per cent load. That's impressive performance from any power supply, particularly one so diminutive, with a depth of just 40mm.

Our tests showed that this PSU was more than 90 per cent efficient at all loads

It's a shame that a PSU at this price uses captive, rather than modular, cables. That means that you can't remove any unwanted connectors and will have to tuck them out of the way inside your case. Not that there's too much choice of connector, with a pair of 6+2 pin PCI Express limiting you to a single graphics cards. The four Molex and six SATA connectors should be enough for most PC's storage needs.

A 120mm fan keeps the Earthwatts EA-550 cool. Under heavy load the fan produced a low hum, but there was discernible coil noise. It's not the quietest of PSUs and this noise may be a little intrusive if you've got your PC in a quiet room and it's sat on your desk.

There's no denying the performance of this PSU and its efficiency is excellent. However, it's also expensive for a captive-cable PSU and it'll take you many years to make back the cost with electricity bills saving. We think it's better to save the money and buy the Be Quiet! Pure Power L8 530W instead.